This invention relates to a centrifugal governor for use with an internal combustion engine, and more particularly to a centrifugal governor of this kind which has an improved function of increasing the quantity of fuel to be supplied to the engine at the start of same.
A conventional centrifugal governor adapted to increase the fuel supply quantity at the start of the engine is known, e.g. from Japanese Patent Publication No. 58-7814, which comprises a control rack for regulating the quantity of fuel to be supplied to the engine, flyweight members radially displaceable in response to the rotational speed of the engine, a tension lever pivotable about a stationary shaft in response to the radial displacement of the flyweight members, an idling spring for urging the tension lever against radially outward displacement of the flyweight members, a torque cam having a cam surface determining a fuel increment to be applied at the start of the engine, a sensor lever having one end engaged by the control rack and another end disposed for engagement with the cam surface of the torque cam, the sensor lever being adapted to engage with the cam surface of the torque cam when the engine is in a starting condition, to cause displacement of the control rack into a fuel increasing position for the start of the engine, a cancelling spring interposed between the torque cam and the tension lever and urging the torque cam with a force dependent upon the angularity of the tension lever in a direction of disengaging the sensor lever from the cam surface of the torque cam, a control lever, and a floating lever interlocking with the control lever operable at human will and having one end engaged by the control rack and another end operatively connected with the tension lever through a guide lever. In the centrifugal governor of this type, when the control lever is operated to a full speed position in order to start the engine, the floating lever is pivotally displaced about its end engaging the guide lever to cause the control rack to be displaced to a fuel increasing position for the start of the engine. This displacement of the control rack to the starting fuel increasing position is realized by engagement of the tip of the sensor lever engaged by the control rack with the cam surface of the torque cam.
However, in cold weather, when the control lever is operated to cause displacement of the control rack to the starting fuel increasing position, the increased frictional resistance of the control rack acts upon the floating lever, which can cause pivotal displacement of the floating lever about its fulcrum engaged with the control rack to displace the guide lever, though then the control rack is also displaced to some degree by the floating lever. This causes pivotal displacement of the tension lever against the force of the idling spring counteracting the pivotal movement of the tension lever. As a result, the torque cam is pivotally displaced by the cancelling spring with its urging force increased by the pivotal displacement of the tension lever, to a position where the sensor lever cannot engage the cam surface of the torque cam, thus impeding the starting fuel increment.